This contract will produce magnetic resonance images of human embryos between stages 10 and 23 from an existing embryo collection. These images will be made available to the scientific community on the contractor's existing World Wide Web site. Images of a total of fifty-four complete embryos will be made available [three cases at each stage from St. 10 to 19 (prior to sexual differentiation) and three cases of each sex for stages 20 to 23].